What a massive public works project. Labor and wealth requirements are hard to conceive, given start of construction before the Persian onslaught.
Themistocles and Trump ...... Build a big beautiful walls!
Looks like the FNG was the designated prow catcher...errr, watcher.
I suspect most of the ships were beached when not in use, and/or tied onshore or close to shore to keep them from drifting off. The ships were build with some kind of truss system to lighten them, which one reason they achieved the velocity for effective ramming. Adding more rows of rowers turned into a bit of an arms race, with the final iteration being a vessel so large it never saw combat. According to Casson, it was a marvel of its age, and after the Romans conquered Greece, they were so taken they towed it to Rome as a trophy and tourist attraction.
The Carthaginians relied for the most part on mercenaries, and the classical period Greek city-states (which are basically coeval) used paid rowers after that initial period when they defeated Persia. Carthage also built a large navy and a harbor facility that served both their military and their commercial needs.
http://www.google.com/search?q=carthage+harbor&sa=X&oi=image_result_group&tbm=isch